1. Field Of The Invention
This invention relates to a silage spreading-unloading rotary sweep apparatus of the hole-forming sleeve type which is used in cylindrical silage-storage tanks or silos.
2. Description Of The Prior Art
Spreading-unloading rotary sweep apparatus of the depending hole-forming sleeve type are commonly used in silage-storage tanks, wherein they function: during a silo filling or loading operation, to spread incoming silage more or less uniformly throughout the cross-sectional area of the tank and contemporaneously form a vertical silage-discharge hole extending centrally through the rising column of silage; and, during a silo unloading operation, to remove silage from the top of the stored column and direct it inwardly toward and into said discharge hole. In some cases, where the augers are spaced above the sleeve, the inwardly flowing silage misses the hole at intervals; in other cases, the unloading silage bridges across the mouth of the discharge hole, all of which is objectionable.
The U.S. patent to Hazen U.S. Pat. No. 3,075,657 granted Jan. 29, 1963 discloses a horizontal rotary sweep mounted on a ring gear in a silo for tracking rotation about the vertical axis of the gear. It has a single long auger which spreads by overflowing a long stepped trough under it and which cooperates with a parallel adjacent rail to unload. It is also provided, under the inner end of the long auger, with a center hole-former, which is short, i.e. of short length in comparison to the usable storage height of any given silo in which it is intended to be used. This short hole-former is in the form of a vertical cylinder closed at both ends and arranged to depend 2 foot to 5 foot from the sweep frame along the common centrally-disposed vertical axes of the ring gear and the sweep unit. This hole-former must be manually removed from the hole before the unloading operation can be instituted.
The U.S. Zeiter U.S. Pat. No. 3,297,177 granted Jan. 10, 1967 discloses a rotary sweep having parallel double long augers arranged so that their outer sides spread during filling while their inner sides cooperate to unload between them. Zeiter's sweep is also provided with a hole-former under the inner ends of his long augers. The center hole-former shown in FIGS. 1-11 comprises: (1) an outer vertically short round hole-forming cylinder of one relatively large diameter; (2) an inner vertically shorter square unloading conduit of such relatively smaller cross-section that its entire periphery is inwardly spaced from the bore of the outer cylinder; and (3) a top comprising a fixed outerpart closing the ceiling space between the outer cylinder and the square conduit and a square lid for closing and opening the top of the square conduit during filling and unloading respectively.
In FIGS. 12-15, Zeiter has a single round hole-forming cylinder and a horizontally slidable flat lid for top closing and opening purposes. Zeiter's hole-former eliminates the necessity of effecting the manual removal of the hole-former before the unloading operation can be instituted. Since hole-formers sometimes jam in the hole during unloading, due to the narrowing of the hole as a result of the weight of the silage above the point where the jamming occurs, Zeiter's hole-forming cylinder is provided with a series of vertically-arranged horizontally-spaced knives attached to and projecting downwardly from the lower end of the cylinder.
The German "Fella" patent No. 1,250,360 published Sept. 14, 1967 discloses a silo storage and unloading device comprising: a silo 1; a center discharge hole provided by an upright series of progressively smaller telescopic sections beginning with section 3 of the largest diameter at the bottom and rotatable section 8 of the smallest diameter at the top; and a diametric silage unloader extending horizontally across the silo with its center mounted on the rotatable top telescopic section 8, one radius section of the unloader carrying a drive wheel which rotates the unloader horizontally while the other radius section of the unloader carries an endless conveyor or "fork chain" 10, the lower run of which sweeps silage lying under its bottom side from the top of the column into a side opening in the top telescopic section 8.
The Henry U.S. Pat. No. 2,110,298 shows a powder unloader using curved scrapers to scrape powdery material from top of a vertical column and move that material inwardly to a center hole maintained by a movable vertical tube. The material drops through the center tube into a solution.
The Weibel U.S. Pat. No. 3,358,856 shows a powder spreader-unloader which, in unloading, rotates and lowers about a tall stationary center pipe having a series of square fixed openings spaced around its circumference and along its height. The unloading sweep auger moves fine grained powder (starch) inwardly and cooperates with scrapers 21 to move starch into pipe 11 where a vertical auger in the pipe scrapes the starch down through the pipe.